The Icy Dragon Sword (commonly abbreviated to "IDS"), like the Fiery Dragon Sword, is a popular sword that is prized for its style. It has a unique look, with its frosty blade (only two twisted "filaments" as a solid core) coming out of the dragon's mouth that acts as the hilt. It only appears with a gold rarity.
Dye only affects the sword's hilt- it does not change the color of the flame. For a sword with a different color flame, consider the Fiery Dragon Sword. If you don't want an elemental mod, think about the Vampiric Dragon Sword.
The Icy Dragon Sword obtained from the Traveler cannot be dyed.
The text on the sword obtained from Gift of the Traveler acknowledges the fact that the swords were originally only found as a low-frequency drop from Ice Imps.
The Traveler's version can be upgraded by both an inscription and a Sword Pommel; the Shiverpeaks version can only be upgraded with a pommel, as its inscription is inherent.
Historical note: The first Icy Dragon Swords were added to the game on December 21st, 2005, but were an undocumented addition (in effect, a hidden Christmas present from ArenaNet).
Historical note: Originally, Icy Dragon Swords were blue by default. As of the May 24th, 2007 update, they are now gold (and therefore exempt from loot scaling). The update was retroactive: all previously blue Icy Dragon Swords became gold items.